. >>> new this morning, president obama is back at the white house after visiting newtown, connecticut. he walked out of marine one after delivering an emotional tribute to the victims of the tragedy. he called on the nation to change so another mass shooting like this one never happens again. >> olivia, josephine. >> more than 900 mourners that packed the high school heard emotional obama admit the country has faild him. >> this is the fourth time we have come together to comfort a grieving community torn apart by mass shooting. >> he will use the power of presidency like the massacre at sandy hook elementary school. >> these tragedies must end. to end them we must change. >> outside an emotional reaction from the shattered community to the president's visit. >> it was very touching, it did mean a lot. >> we have six kids. that is how we will be judged. >> new and chilling details about adam lanza's past have emerged. according to the governor the rampage ended ten minutes after it began when lanza where he opened fire heard wailing sirens from law enforcement approaching and shot him